This invention relates to a device for dispensing dry particles, particularly polymeric erosion control agents such as polyacrylamides, in irrigation ditches or furrows for soil stabilization and improved irrigation.
In agricultural areas where fields are irrigated by running water into furrows, erosion of the soil is a major problem. While furrow irrigation has significant advantages including water saving and less costly equipment, especially as compared with overhead sprinklers, it also has some disadvantages. In particular, furrow or ditch irrigation causes significant soil erosion as the water running along the furrow washes away soil. In some areas, erosion of topsoil can amount to between 2.8 and 28 tons per acre during a 24 hour watering interval.
In addition, this form of irrigation can remove valuable pesticides and fertilizers that become pollutants in the waterways to which they run, and the soil itself can become less porous, and therefore less able to accept the irrigation water and convey it to plant roots, as fine clay particles settle out of the water and clog soil pores.
It has been found that certain polyacrylamides can alleviate these problems and thereby make furrow irrigation a more useful and less destructive irrigation technique. Polyacrylamides are long-chain polymers that reduce the amount of soil carried by the irrigation water and reduces the negative effect of the erosion on soil porosity.
Polyacrylamides are employed in furrow irrigation by adding selected quantities of the substance in a powder-like form to the irrigation water as the water is dispensed or flows into the field. Dry polyacrylamide particles are highly sensitive to moisture. When the dry polymer is exposed to moisture, the particles tend to become sticky and agglomerate. As the amount of moisture increases, the substance becomes increasingly sticky and no longer flows as a powder.
Polyacrylamide particles are presently dispensed into irrigation ditches or furrows using either belt feeders or auger-type systems. ARK Fisheries, for example, offers a belt feeder that employs an endless belt loop system located within a box container. The polyacrylamide particles are placed on the top of the belt loop. As the belt moves forward, a portion of the polyacrylamide particles fall over the edge and out an opening provided through the bottom of the box. Another company, Andersen RandD, offers a feeding system that uses an auger mechanism to dispense polyacrylamide from the container. The auger mechanism requires a twelve volt battery for operation.
The teachings in U.S. Pat. No. 5,450,985 (xe2x80x9cMeulemanxe2x80x9d) disclose a dispenser system for the application of dry polyacrylamide. The polyacrylamide is dispensed from a container through the action of an impeller provided over the top of an opening in the base of the container. The polyacrylamide falls through the opening into a hose and feed tube to a discharge unit provided over an irrigation furrow. The discharge unit includes a twelve volt fan that draws air into the discharge unit and blows the air past the outlet of the feed tube. Meuleman suggests that the discharge of air past the outlet prevents moisture, particularly in humid environments, from causing the polyacrylamide particles to agglomerate within feed tubes.
An object of the present invention is to provide an apparatus for dispensing dry erosion control agent into irrigation water.
Yet another object is to provide such a dispensing apparatus which is operable at locations remote from a conventional power source for long intervals of time.
Briefly described, the invention relates, in a first aspect, to a device for dispensing dry particles into a body of water including a material drop tube having an inlet opening and a second opening containing dry particles, a motor attached to said material drop tube, a shaft responsive to said motor, a drum roller having a cylindrical outer surface, wherein the drum roller is positioned horizontally beneath the second opening in said material drop tube and rotates in response to said motor and axle and a direct current power source delivering about six volts or less. Preferably, the direct current power source is a battery delivering about three volts or less. The device may further include a programmable controller connected to said motor adapted to operate said motor at variable speeds for specified periods of time and to thereby dispense particles at variable rates for specified periods of time. The programmable controller can be powered, in whole or in part, by solar cells. The programmable controller and motor can be powered by separate power sources. In a particularly preferred embodiment, the programmable controller and motor are powered by a battery delivering about three volts or less.
The device is particularly suited for the delivery of dry particles that acts as a polymeric erosion control agent in an irrigation ditch or furrow. The dry particles are preferably polyacrylamide particles.
The present invention further relates to an irrigation process including the steps of feeding dry particles into a device substantially as described above, activating the motor of said device to cause rotation of the drum roller and thereby discharging the dry particles from the material drop tube onto the cylindrical outer surface of said drum roller.